1 . Fire ants dig tunnels efficiently by only a small percentage of the group doing most of the work. Free-loaders just sit around while their hard-working colleagues get things done. But might freeloaders actually be necessary for society to function efficiently? The answer could be yes.
Fire ants are highly social organisms. So, Goldman, a physicist at Georgia Tech, and his colleagues wanted to know how individual ants knew what to do without a central leader issuing orders. To find out, Goldman's team labeled individual fire ants with paint and then watched them dig their narrow tunnels —barely wide enough for two workers. Turns out, just 30 percent of the ants did 70 percent of the labor. “I was surprised that we ended up with so few workers actually doing the work at any one time. ” A quarter of the ants never even entered the tunnel. Others crawled inside, but left without digging single grain of dirt. These idling behaviors ensured the tunnels did not get clogged with insect traffic, which would make the construction process stop.
And when the scientists removed the five hardest working ants from the colony, others immediately jumped in to compensate (补偿) — with no reduction in the group's productivity. It seems that it doesn’t matter which ants are working or freeloading at a given time, as long as there is some division of labor to keep the tunnels flowing smoothly. The findings are in the journal Science.
The study could have implications for robotics. Imagine groups of robots sent to search rubble (碎石) for disaster survivors. Or nanobots (纳米机器人) coursing through our bodies to diagnose illness and deliver targeted medical treatment. Such robot groups will need to avoid getting jammed up in tight spaces. It might be necessary to program them so some just sit back and watch their comrades work.
1. How do fire ants get the work done when digging tunnels?| A．Only the leaders do most of the work. |
| B．They all work under the order of one leader. |
| C．They all cooperate together to do the work efficiently. |
| D．Individual fire ants know their tasks and work efficiently. |
| A．crowded | B．transported |
| C．organized | D．covered |
| A．The ants will have no idea what to do. |
| B．Other ants will take their place and do the work. |
| C．The tunnels will get blocked and the work will stop. |
| D．The leader will compensate them and give them food as the reward. |
| A．fire ants are the most diligent insects. |
| B．scientists may diagnose illness more easily. |
| C．people may feel happy when they watch their colleagues do nothing. |
| D．scientists can deal with robotics better when coming to specific programs. |
2 . China is determined to land its astronauts on the moon and set up a scientific station there,according to a project leader.
Zhou Yanfei,deputy chief designer of China's manned space program,said on Friday that China wishes to use the manned lunar missions to carry out scientific surveys and technology demonstrations,explore ways to develop lunar resources and strengthen the nation's space capabilities.
＂A new wave of lunar explorations has been emerging in the world,with participants aiming to make sustainable missions to deepen knowledge of the moon and exploit resources there,"he said in a report delivered at the 2020 China Space Conference in Fuzhou,Fujian province."Unlike other nations,China must depend on its own science and technology to realize our goals."
The country is independently able to land its astronauts on the moon because it has the technologies,a group of well-trained,innovative professionals and high-efficiency research and management systems,Zhou said."However,our existing carrier rockets can't perform landing missions to the moon because they are not powerful enough.The Shenzhou- series manned spaceships are not suitable for lunar expeditions.We don't have a lunar landing capsule,"he said."Our ground support system was designed for operations in low-Earth orbit rather than on the lunar surface.
To solve the problem, we set out to produce a powerful launch vehicle. Zhou said researchers thought about two approaches-making a new heavy-lift rocket,or adjusting the next-generation rocket designed to carry astronauts,which is under development.Researchers prefer the latter approach because it would be easier to design and make and would become operational earlier.
The new rocket is being designed at the China Academy of Launch Vehicle Technology.Its main body will be 87 meters tall,with a diameter of 5 meters,which would make it almost twice as tall as the Long March 5,currently the biggest of China's rockets.
1. Which is NOT the goal of the manned lunar mission?| A．To explore lunar resources. |
| B．To perform scientific experiments. |
| C．To set up a scientific station. |
| D．To strengthen the national space power. |
| A．China is not capable of pursuing the manned lunar program. |
| B．There are still difficulties in pursuing the manned lunar program. |
| C．There are a series of steps in the Manned Lunar program. |
| D．It is manageable to carry out the Manned Lunar program. |
| A．Nations must depend on themselves to explore the moon. |
| B．The Long March 5 is the biggest of China's rocket. |
| C．The newly-designed rocket will not carry astronauts. |
| D．Producing a powerful launch vehicle is the most difficult part in the program. |
| A．The new rocket is big enough to perform landing missions. |
| B．The new rocket is being made to launch lunar spaceship. |
| C．China's scientific power has improved. |
| D．The new rocket will be put into use soon. |
3 . Chinese restaurants began to open in America in the mid-19th century, mainly on the west coast where the first immigrants landed. They mostly served an Americanized version of Cantonese cuisine, chop suey, egg fu yung and the like. In that century and much of the 20th,the immigrants largely came from China's south-east, mainly Guangdong province.
After the immigration reforms of 1965, Chinese migrants from other regions started to arrive. Restaurants began calling their food "Hunan” and “Sichuan". Though their food rarely resembled what was actually eaten in those regions, it was more diverse and boldly spiced than the sweet, fried stuff that defined the earliest Chinese menus. By the 1990s adventurous diners in cities with sizeable Chinese populations could choose from a variety of regional cuisines. A particular favorite was Sichuan food, with its addictively numbing fire due to peppercorn.
Yet over the decades, as Chinese food became universal, it also came to be standardized. There are almost three times as many Chinese restaurants in America (41,000)as McDonald's. Virtually every small town has one. And generally the menus are consistent: pork dumplings （steamed or fried);the same two soups(hot and sour, wonton);stir-fries listed by main ingredient, with a pepper icon or star indicating a slight trace of chilli-flakes. Dishes over$10 are grouped under "chef's specials".
Until recently, the prices varied as little as the menus and they were low. Eddie Huang, a Taiwanese-American restaurateur, recalls how his newly-arrived father kept his prices down because" immigrants can't sell anything full-price in America."
Americans have traditionally been willing to pay through the nose at French or Italian joints （where, in fact, Latinos often do most of the cooking).And every city has its pricey sushi bars and expensive tapas restaurants(tapas, as one joke goes, is Spanish for"$96 and still hungry").
Mr. Huang is right that Americans have long expected Chinese food to be cheap and filling. One step up from the urban takeaway, with its fluorescent lighting, is the Chinese restaurant with its red doors and fake lions standing guard, exotic enough to be special, but still affordable enough for a family to visit once a week when nobody feels like cooking. Even the superior outlets were cheap for what they served.
But now things are changing. Mr. Huang sells delicious stuffed buns in New York and Los Angeles for$5.50 each and encourages other immigrants not to undervalue their work.
Meanwhile, although racism persists, the previous discrimination of earlier ages has been fading. Since the Chinese-American population is six times what was 40 years ago, Americans overall are much more familiar with Chinese people and their cooking, all of which means that the new fancy breed of Chinese restaurants draws a heartening mix of Chinese and non-Chinese diners.
1. We can learn from the first three paragraphs that_| A．Cantonese cuisine was well received by Americans in the 19th century |
| B．Those so-called Hunan or Sichuan food in America tasted just as what was actually eaten in those regions |
| C．Nowadays Chinese restaurants are almost twice more than McDonald's in America |
| D．Americans prefer Hunan food because they have been addicted to peppercorn |
| A．Americans have long expected Chinese food to be cheap and filling. |
| B．Earlier immigrants couldn't sell anything full-price in America. |
| C．Americans prefer French and Italian food. |
| D．Chinese restaurants face fierce price competition from other restaurants. |
| A．In order of importance. |
| B．In order of place. |
| C．In order of time. |
| D．In order of position. |
| A．Immigration on a plate. |
| B．Americans' favourite cuisine. |
| C．Prejudice against Chinese immigrants. |
| D．Route to success. |
4 . It’s normal for teens to want to stay connected with friends and social circle, but what about that happening in the middle of the night? The Journal of Youth Studies recently published new research showing that one in five teens from 12 to 15 regularly wake to spend all night on social media (社会媒体). Not surprisingly, the research also showed that these social night owls were three times more likely than others to feel tired at school and that girls were more likely than boys to be called to office.
The blue light produced by cell phones and computers makes the brain to stay awake, so it's easy to see why a teen might be up all night. A study in Psychological Science showed the same brain reaction: when teens saw large numbers of “likes” on their posts, they stayed awake with excitement as if they had eaten chocolates or won money. Besides not catching up on sleep and interrupting their sleep cycle, teens may never fully enter deep sleep that may be responsible for brain development and learning.
Considering about 72 percent of children from 6 to 17 sleep with some electronic media in their bedrooms, parents need to set rules sooner rather than later.
“Providing access (使用机会) to social media is a favor that children can earn and also lose,” Janie Feldman, an expert who treats sleep disorders (紊乱), reminds parents, “The bad effect is clear. So teens and parents should discuss and agree on its use, timing and access. When teenagers agree to the rules, it’s easier for parents to control how much time they use the phones or computers.”
1. What does the underlined part “night owls” in paragraph 1 refer to?| A．Girls often called to office. |
| B．Teens who stay up late on social media. |
| C．Teens who are busy with their homework at night. |
| D．Boys regularly waking in the middle of the night. |
| A．They are too excited to go to sleep. |
| B．They fall asleep easily and happily. |
| C．They are too excited to go to school. |
| D．They decide to make more good friends. |
| A．Making rules about media access together with their children. |
| B．Getting their children to do homework through computers. |
| C．Encouraging their children to stay connected with online friends. |
| D．Stopping their children from using cell phones. |
| A．Deep sleep makes a big difference to brain development. |
| B．Kids are trying to win back the trust of their parents. |
| C．Social media may have a bad effect on all kinds of people. |
| D．Social media may cause teens’ sleep disorders. |
